High pressure air systems, for example the type used in mines and the like, commonly have many pipes distributed to different areas of the system involving many pipe couplings where there is a potential for leakage and loss of pressure. A typical pipe coupling joins two pipe ends which have annular grooves formed therein to receive respective annular sealing members therein. The pipe coupling comprises a metal body arranged to be clamped over the pipe ends and the sealing members received in the grooves therein to both join the pipe ends to one another as well as to seal the pipe ends to the clamp body of the pipe coupling. The small cross section of sealing material in the grooves has potential to deteriorate quickly in the corrosive environment of mines and the like so that the resulting pipe couplings leak and lose pressure. The loss in air pressure must be overcompensated by pressurizing more air into the system which consumes costly operating resources. Repairing leaking pipe couplings typically requires the air system to be shut down to remove the coupling body and replace the sealing members. Shutting down the air system however results in costly down time. In the example of mines, the loss of productive time is more costly than the extra operating costs of overcompensating for leaks in the air pressure system.
Various pipe repair devices have been proposed in the prior art for repairing a leak in a pipe which may not require shutting down to remove pressure from the pipe. Examples can be found in the following U.S. Patents, U.S. Pat. No. 6,220,302 by Nolley, U.S. Pat. No. 7,126,579 by Borland, U.S. Pat. No. 2,230,287 by Curtis, U.S. Pat. No. 732,400 by Dresser et al and U.S. Pat. No. 4,756,338 by Guyatt et al.
Typical prior art configurations involve a small sealing member which is clamped between a rigid clamping body and the pipe resulting in many sealing surfaces which the sealing member must be in contact with. Failure of the seal can occur either at the interface of the sealing member with the pipe, or at the interface of the sealing member with the rigid clamp body surrounding the pipe so that there is a high probability of failure. Also the sealing material is prone to quick degradation in corrosive environments when provided in a small cross section between a clamped body and a pipe.